In the early 21st century, educational reform in many countries shifted to put more emphasis on learning-oriented strategy for change and to focus on empowerment of teachers and self-sustaining change in school. Consequently, teacher quality has developed into a core innovation issue of school education in many countries. Recently "lesson study" as an Japanese approach of Jugyou Kaizen (improving teaching), which emphasize what actually goes on in the classroom and how the quality of teaching can be improved, has become an alternative model of core innovation of school education and improving teaching-learning process in the world. This paper tries to examine this educational movement in practice, the outcomes and challenges as well as guideline for implementing it in other nations and educational context. [This paper was published in "Child Research Net."]